New images show the extent of devastation caused by Hurricane Matthew in Haiti, with one town virtually wiped out and at least 23 people dead.
The death toll is expected to rise amid concern over an area in the south-west which remains largely cut off.
Images from one of the towns, Jeremie, show hundreds of flattened houses.
The hurricane has gone back up to a Category Four storm, the second highest hurricane classification, as it heads for the US state of Florida.
Hurricane Matthew is currently pounding the Bahamas, after slicing through Haiti and Cuba. It is the most powerful Caribbean storm in nearly a decade.
Haiti's civil protection service has confirmed 23 fatalities, but Reuters news agency, quoting local officials, put the death toll at the much higher figure of 98.
The south-western town of Jeremie was "pretty much wiped out from the seaboard all the way to the cathedral", a radio host in Haiti's capital of Port-au-Prince told the BBC on Thursday.
He said the town had been virtually cut off from the rest of the world because of broken down communications since the hurricane.
"The devastation that we are seeing is horrible...The town is really in dire straits and it's very, very bad down there."
A presidential election due this weekend in Haiti has been postponed because of the hurricane, which has left destruction across the Caribbean region.
Four people were also killed in the neighbouring Dominican Republic.
It has intensified as it moves towards the US state of Florida, where US residents have been warned to prepare for a "direct hit".
Florida Governor Rick Scott said his state could be facing its biggest evacuation ever.
Matthew battered Haiti with winds of up to 230km/h (145mph) on Tuesday. The country is one of the world's poorest, with many residents living in flimsy housing in flood-prone areas.
One official for aid agency Oxfam told the BBC that more than 10,000 people had been displaced in the south alone.
Officials are concerned about the full extent of the damage in the Grand Anse area on the southern tip of the island - where Jeremie lies - which was directly in the storm's path.
A key bridge has been destroyed, roads are impassable and phone communications have gone down.
Mourad Wahba, the UN special representative for Haiti, said hospitals were overflowing.
Among the damaged buildings were schools and churches due to be used as polling stations in Haiti's election. A new date for the much-delayed vote has not yet been announced.
At the scene: Tony Brown, BBC News, Haiti
We only began to see the real destructive force of Hurricane Matthew once we moved towards the south-west of the country.
Trees fallen, banana crops uprooted and flattened, houses under water and men and women trying to get the debris out of the way.
It was noticeable how the people we passed were coping alone. There were no army or police around to help.
Even the aid agencies are struggling to move around this damaged corner of the country.
Why Haiti is vulnerable to disasters
Hurricane Matthew has left a trail of destruction across the Caribbean, but nowhere has the devastation been more severe than in Haiti.
The poorest country in the Americas, Haiti has long been particularly vulnerable to natural disasters. Six years after an earthquake killed more than 200,000 people and displaced 1.5 million, tens of thousands of quake victims still live in temporary shelters.
More than half of Haiti's city-dwellers live in overcrowded shantytowns that take the full force of any earthquake, hurricane, or disease outbreak. An ongoing cholera epidemic, triggered by the arrival of UN troops after the 2010 quake, has killed thousands of people.
Massive deforestation has also led to soil erosion, leaving hillside huts and poorly-built houses in the capital, Port-au-Prince, dangerously exposed. The consequence in rural areas, where many depend on small plots of land for their food, is that topsoil is often washed away.
Political instability and corruption have been a factor. Without effective government for decades, Haiti currently ranks 163rd out of the 188 countries on the UN Human Development Index. It spends little on storm defences.
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